The quark transition via which the \(B\rightarrow D^{(*)}\tau \nu \)  proceeds is \(b\rightarrow c\tau \nu \) . Note, however, that the flavor of the neutrino is, of course, unobservable. It could be \(\nu _\tau \) , in which case the process respects the accidental lepton flavor symmetry of the SM. There is no reason, however, that the symmetry is respected by new physics, particularly when the new physics violates lepton flavor universality, so that the neutrino could also be \(\nu _\mu \)  or \(\nu _e\)  or some combination of the three flavors. This possibility has been discussed very little in the literature (for an exception, see [1]}), and we aim to fill in this gap. We ask three main questions:
